Hi Ike,
Yes, I did something very similar. I delete my temporary internet files folder on a regular basis as a matter of routine, but did not think that such a huge amount of space would be taken up in such a short space of time by temp files. Nonetheless, after deleting them, my disc space did almost go back up to normal. Another thing I did (after making sure there were no viruses/malware present) was to switch off System Restore and then turn it back on again. Generally speaking this is not a recommended action, but it gave me back 8GB! If everything else is running smoothly, I think that periodic flushing of the restore points is a GOOD thing to do, so long as you immediately turn it back on again. Who really needs months and months worth of restore points anyway? Please don't just do this because I've done it, but it is definitely something to consider.
Hope all goes well with the exams!
Best wishes,
Ian